09-16-2005
Quote:
Originally Posted by mridula
i m aware abt fread(), fwrite(), fseek()... but using these allows the pointer to be moved 1 character at a time. Is there a way i could jump directly to a line if i know the line number?
not so !
with fseek - file pointer can be repositioned anywhere within the file
if the file records are of standard length ( for ex: each and every line of the file contains x chars)
then to switch to nth line
fseek(filePtr, (n * x) + 1, SEEK_CUR);
(assuming \n as the default line separator in the file)
SEEK_CUR is the whence position.
use
man fseek you will get the required info
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FREAD(3S) FREAD(3S)
NAME
fread, fwrite - buffered binary input/output
SYNOPSIS
#include <stdio.h>
fread(ptr, sizeof(*ptr), nitems, stream)
FILE *stream;
fwrite(ptr, sizeof(*ptr), nitems, stream)
FILE *stream;
DESCRIPTION
Fread reads, into a block beginning at ptr, nitems of data of the type of *ptr from the named input stream. It returns the number of items
actually read.
If stream is stdin and the standard output is line buffered, then any partial output line will be flushed before any call to read(2) to
satisfy the fread.
Fwrite appends at most nitems of data of the type of *ptr beginning at ptr to the named output stream. It returns the number of items
actually written.
SEE ALSO
read(2), write(2), fopen(3S), getc(3S), putc(3S), gets(3S), puts(3S), printf(3S), scanf(3S)
DIAGNOSTICS
Fread and fwrite return 0 upon end of file or error.
4th Berkeley Distribution May 15, 1985 FREAD(3S)